Prosecutors portrayed Anthony as a young mother who killed her daughter because she got in the way of her love life.
"Something needed to be sacrificed, that something was either the life she wanted or the life thrust upon her. She chose to sacrifice her child," prosecutor Jeff Ashton said during his 90-minute argument.
Defense attorney Jose Baez said the prosecutors' case was so weak they tried to portray Anthony as "a lying, no-good slut" and that their forensic evidence was based on a "fantasy." He said Caylee's death was "an accident that snowballed out of control."
Prosecutors contend Caylee was suffocated with duct tape by a mother who then crafted elaborate lies to mislead investigators and her parents. Defense attorneys countered that the toddler accidentally drowned in the family swimming pool, and that her mother in fact was hiding emotional distress caused by alleged sexual abuse from her father. Her father has denied that claim.
Judge Belvin Perry ruled Sunday morning that there was no evidence of such a claim and that the defense could not allude to it in closing arguments. He indicated that the prosecution's rebuttal case would be given Monday, followed by jury deliberations.
Baez began his closing argument by telling jurors they have more questions than answers, including the biggest: How did Caylee die? Neither prosecutors nor the defense have offered firm proof of how Caylee died.
"It can never be proven," he said.
He spent most of his four-hour argument attacking the prosecution's forensic evidence. He said the prosecution's air analysis of the trunk of Anthony's car, which allegedly showed air molecules consistent with decomposition, could not be duplicated. He said no one could prove a stain found in the trunk was caused by Caylee's body decomposing there. And witnesses showed maggots found in the trunk came from a bag of trash that was found there, he said.
"They throw enough against the wall and see what sticks. That is what they're doing ... right down to the cause of death," Baez said. He later conceded his client had told elaborate lies and invented imaginary friends and even a fake father for Caylee, but he said that doesn't mean she killed her daughter.
He also attacked Anthony's father, George Anthony, as unreliable. He said that a suicide note that George Anthony wrote in January 2009 that claimed no knowledge of what happened to Caylee was self-serving and that the attempt was a fraud. He said George Anthony claimed he was going to kill himself with a six-pack of beer and some high-blood pressure medicine.
Earlier during prosecution's closing argument, Anthony appeared mostly stone-faced for about the first 45 minutes, but she began to cry when Ashton said the story that Caylee drowned was also false.
Ashton, the prosecutor, said Caylee's death wasn't an accident because three pieces of duct tape were placed on her face - one on the mouth, one on the nose and one over those to be "thorough."
The jury is expected to begin deliberating after the defense finishes its closing argument. Perry said those deliberations will continue Monday on the July Fourth holiday if necessary.
The case has played out on national TV since Caylee's disappearance in the summer of 2008 and continued through her mother's trial, with spectators traveling from all over the U.S. to jockey for coveted seats in the courtroom gallery. Anthony, a single mother, was 22 when her daughter died. No one has come forward as the father of Caylee.
Ashton began his closing argument by showing a video of Anthony playing with Caylee, causing Anthony to apparently choke back tears. But she quickly regained her composure.
He then told the jury that Anthony worried Caylee was getting to the age where she would have told Anthony's parents that the woman was spending her days and nights with her boyfriend - not going to work and leaving Caylee with a nanny.
"Casey is very bright," Ashton said. "Her lies are very detailed. ... But when Casey wants to do what Casey wants to do, she finds a way."
The prosecutor then described the lies Anthony told her parents, George and Cindy Anthony, about why she couldn't come home and why she couldn't produce Caylee after the toddler was last seen June 16, 2008: that she was with a nanny named Zanny, a woman who doesn't exist; that Anthony and her daughter were spending time in Jacksonville with a rich boyfriend who doesn't exist; and that Zanny had been hospitalized after an out-of-town traffic accident and that they were spending time with her.
It only fell apart, Ashton said, a month later when a junk yard told George and Cindy Anthony their daughter's car had been towed. When they picked it up, they discovered a foul odor - George Anthony, a former police officer, and the tow yard operator said it smelled like human decomposition.
Cindy Anthony then tracked down her daughter. When she couldn't produce Caylee, her parents called police. Casey Anthony then told investigators she worked at Universal Studios theme park as an event planner. She went so far as to take them there, talk her way past security, take them to an office building. She gave up the lie as she was walking down the hall.
Ashton then attacked the defense contention that Caylee drowned and that George Anthony helped Casey Anthony cover it up. No one faced with an accidental drowning would do that instead of calling 911, Ashton said.
"It is a trip down a rabbit hole into a bizarre world where men who love their granddaughters find them drowned and do nothing," Ashton said. "Where men who love their granddaughters take an accident, a completely innocent act, and make it look like a murder for no reason. A world where a man who buries his pets will take the granddaughter who was the love of his life and throw her in a swamp."
Baez conceded that Anthony told elaborate lies, but he said those inventions should have signaled to investigators that "there's something wrong with this girl."
"Instead, they had a murder case, and that was it. That was all they were interested in was evidence of murder. There's nothing sexy about a drowning," Baez said.
Judge Perry angrily stopped Baez's closing arguments after he referred to Ashton as "this laughing guy." Television showed Ashton smiling behind his hand at Baez's contention that the prosecution's forensic evidence was based on fantasy. One of Perry's written orders is that the attorneys not show emotion to the other side's statements.
Ashton apologized and said he tried to hide his expressions. Baez also apologized. Perry warned all of the attorneys that any other incidents would result in that attorney's removal from the trial.
Casey Anthony has pleaded not guilty to first-degree murder. She could face a possible death sentence or life in prison if convicted of that charge.
Anthony also is charged with aggravated child abuse, aggravated manslaughter of a child and four counts of providing false information to law enforcement. The child abuse and manslaughter charges each carry a 30-year prison term if convicted.